<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <title>Page Title</title>
  <style>
    .triangle {
      width: 0;
      height: 0;
      border: 10px solid;
      border-color: #bbffcc transparent transparent transparent;
      transform: translate(20px, 40px);
    }
  </style>
</head>
<body>
  <div class="triangle"></div>
</body>
</html>